jdbcTemplate分页封装

1.JdbcTemplateExtend.java

public class JdbcTemplateExtend extends JdbcTemplate
{
private DataSource dataSource;
/**
* 默认构造器，调用此方法初始化，需要调用setDataSource设置数据源
*/
public JdbcTemplateExtend()
{
}
/**
* 初始构造器
*
* @param dataSource
* 数据源
*/
public JdbcTemplateExtend(DataSource dataSource)
{
this.dataSource = dataSource;
super.setDataSource(dataSource);
}
/**
* 普通分页查询<br>
* <b>如果结果结合比较大应该调用setFetchsize() 和setMaxRow两个方法来控制一下，否则会内存溢出</b>
* @see #setFetchSize(int)
* @see #setMaxRows(int)
* @param sql
* 查询的sql语句
* @param startRow
* 起始行
* @param rowsCount
* 获取的行数
* @return
* @throws DataAccessException
*/
@SuppressWarnings("unchecked")
public List<Map> querySP(String sql, int startRow, int rowsCount)
throws DataAccessException
{
return querySP(sql, startRow, rowsCount, getColumnMapRowMapper());
}
/**
* 自定义行包装器查询<br>
* <b>如果结果结合比较大应该调用setFetchsize() 和setMaxRow两个方法来控制一下，否则会内存溢出</b>
* @see #setFetchSize(int)
* @see #setMaxRows(int)
* @param sql
* 查询的sql语句
* @param startRow
* 起始行
* @param rowsCount
* 获取的行数
* @param rowMapper
* 行包装器
* @return
* @throws DataAccessException
*/
@SuppressWarnings("unchecked")
public List<Map> querySP(String sql, int startRow, int rowsCount, RowMapper rowMapper)
throws DataAccessException
{
return (List) query(sql, new SplitPageResultSetExtractor(rowMapper, startRow,
rowsCount));
}
public DataSource getDataSource()
{
return dataSource;
}
public void setDataSource(DataSource dataSource)
{
this.dataSource = dataSource;
super.setDataSource(dataSource);
}
}

2.SplitPageResultSetExtractor.java

public class SplitPageResultSetExtractor implements ResultSetExtractor
{
private final int start;// 起始行号
private final int len;// 结果集合的长度
private final RowMapper rowMapper;// 行包装器
public SplitPageResultSetExtractor(RowMapper rowMapper, int start, int len)
{
Assert.notNull(rowMapper, "RowMapper is required");
this.rowMapper = rowMapper;
this.start = start;
this.len = len;
}
/**
* 处理结果集合,被接口自动调用，该类外边不应该调用
*/
public Object extractData(ResultSet rs) throws SQLException, DataAccessException
{
List result = new ArrayList();
int rowNum = 0;
int end = start + len;
point: while (rs.next())
{
++rowNum;
if (rowNum < start)
{
continue point;
}
else
if (rowNum >= end)
{
break point;
}
else
{
result.add(this.rowMapper.mapRow(rs, rowNum));
}
}
return result;
}
}